The present invention relates to a method for processing a silver halide color photographic material, and more particularly to a processing method capable of rapidly bleaching/fixing a silver halide color photographic material.
Generally, to obtain a color image by processing an imagewise exposed silver halide color photographic material, the color developing process is followed by a process for bleaching the photographic material in a processing bath capable of bleaching the produced metallic silver.
As the processing bath capable of bleaching metallic silver, bleaching bath and bleach-fix bath are known. Where a bleaching bath is used, generally the bleaching process is followed by an additional fixing process using a fixing agent. There are also cases where a bleach-fix process takes place which effects the bleaching and fixing at the same time.
In the bleachability-having processing bath for use in processing a silver halide color photographic material, inorganic oxidation agents such as red prussiates, dichromates, etc., are extensively used as the oxidation agent for bleaching image silver.
However, it is pointed out that the bleachability-having bath containing such an inorganic oxidation inhibitor has some serious disadvantages. For example, red prussiates and dichromates are relatively excellent in the power of bleaching silver image, but are possibly decomposed by light to produce cyanide ions and hexavalent chromium ions, which are harmful to the human body, thus having a nature unfavorable for the prevention of environmental pollution. And any of these oxidation agents has a very strong oxidation power, so that it is difficult to make the agent present together with a silver halide solvent (fixing agent) in a same bath, and therefore it is almost impossible to use such the oxidation agent in a bleach-fix bath, thus making it difficult to accomplish the object of speeding up and simplifying the processing of a photographic material. Further, the processing bath containing such the inorganic oxidation agent has the disadvantage that its waste liquid after processing can hardly be recycled.
In contrast to this, a processing bath containing a metallic complex salt of an organic acid such as an aminopolycarboxylic acid has become used as the one which causes little or no environmental pollution and which can meet the need for speeding up and simplifying the processing and whose waste fluid can be recycled. However, the processing bath which uses such the metallic complex salt of an organic acid, since its oxidation power is weak, has the disadvantage that the rate (oxidation rapidity) of bleaching the image silver (metallic silver) formed in the developing process is low. For example, iron(III) complex salt of ethylenediaminetetraacetic acid which is consiered strong in the bleaching power among those aminopolycarboxylic acid metallic complex salts is practically used in part for a bleaching or bleach-fix bath, but lacks its bleaching power when used in the processing of high-speed silver halide color photographic materials comprised mainly of a silver bromide or silver iodobromide emulsion, particularly color negative film and color reversal film for photographing use containing silver iodide as the silver halide, and very slight marks of image silver remains even when the bleaching takes place for a long period of time, i.e., no perfect desilverization can be carried out. This tendency appears significantly particularly in a bleach-fix bath wherein an oxidation agent is present together with a thiosulfate and a sulfite because its oxidation-reduction potential is lowered. Especially, the desilverizability is conspicuously worsened in the case of those high-speed silver iodide-containing silver halide color photographic materials for photographing use which contains black colloidal silver used for the antihalation purpose.
Further, there is a core/shell emulsion, which is the aforementioned silver iodide-containing high-speed emulsion and fine-grained and which has lately been developed as the silver halide emulsion whose silver is efficiently utilized so as to meet the need for the protection of resources. This core/shell emulsion is a monodisperse core/shell emulsion prepared in the manner that a preceding silver halide is utilized as a crystalline nucleus, and on this are sequentially superposed the subsequent precipitates with the respective precipitate compositions or process environment deliberately controlled. The above-mentioned core/shell-type high-speed emulsion, which contains silver iodide in the core and/or the shell thereof, has very favorable photographic characteristics, but it has now been found that, where the emulsion is applied to a silver halide color photographic material, when processed in a conventional bleach-fix bath, its bleach-fixability of the developed silver and silver halide is very unsatisfactory.
That is, the developed silver of a photographic silver halide emulsion containing not less than 0.5 mole% silver iodide, particularly the developed silver of silver halide grains containing not less than 0.5 mole% silver iodide in both the core and shell thereof, even if excellent in the sensitivity, graininess, covering power, etc., in the case of a color photographic material whose developed silver must be bleached, is very unsatisfactorily bleached because the developed silver is different in the form from conventional ones. Particularly, among emulsions there are those which use plate-form silver halide grains as described in, e.g., Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) Nos. 113930/1983, 113934/1983, 127921/1983 and 108532/1983. Such the emulsion is said to require no increase in the using amount of silver even if the number of photons caught by the silver halide grains increases and also said to cause no deterioration of the resulting image quality due to the plate-form silver halide grains. However, even these plate-form silver halide grains have the disadvantage that the developed silver formed therefrom in the development by a p-phenylenediamine-type color developing agent is inferior in the silver bleach. Accordingly, a strong demand has been made for the advent of a processing bath capable of rapidly bleaching/fixing silver halide color photographic materials comprising a silver iodide-containing core/shell emulsion and/or a plate-form silver halide emulsion, which are excellent as described above, and an antihalation layer consisting of black colloidal silver.